• Journal of the Korean Vacuum Society
• /
• v.8 no.2
• /
• pp.141-147
• /
• 1999

The electrochromic characteristics of tungsten oxide films are largely affected by deposition conditions, such as substrate temperature and gas flow rate and also post-annealing. We have considered gas flow rate and temperature as important factors having an effect on an electrical, optical phenomenon and structural variation of $WO_3$ . The tungsten oxide films were deposited onto ITO(20$\Omega\box$, 1000$\AA$) using rf magnetron sputtering method. In particular, the films deposited at room temperature were annealed at various temperatures in air. All specimens had crystal structure except one being deposited at room temperature with nearly amorphous-like structure. The specimen deposited at $100^{\circ}C$ had a structure in which the increase in deposition temperature. The specimen deposited at $100^{\circ}C$ had a structure in which the cations$(Li^+)$ are easily movable because of void boundaries induced by regularly arrayed large grains. The specimen deposited at $300^{\circ}C$ had a dense structure with small grains but it exhibited the large mobility and charge density in $WO_3$ because of distinct grain boundaries.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.06a
• /
• pp.446-447
• /
• 2007

Aluminisum-doped zinc oxide (AZO) films are attractive materials as transparent conductive electrode because they are inexpensive, nontoxic and abundant element compared with indium tin oxide (ITO). In our paper, AZO films have been deposited on glass (coming 1737) substrates by RF magnetron sputtering. The AZO film was post-annealed at $600^{\circ}C$, $800^{\circ}C$ for 2 hr with $N_2$ atmosphere, respectively. We investigated that the electric properties and qualitative analysis of AZO films, which measured using the methods of Hall effect, X-ray photoelectron spectroscopy (XPS).

• Journal of the Korean Ceramic Society
• /
• v.38 no.10
• /
• pp.871-875
• /
• 2001

Cobalt silicidation at sidewall spacer edge of Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) with post annealing treatment for capacitor forming process has been investigated as a function of dopant species. Cobalt silicidation of nMOSFET with n-type Lightly Doped Drain (LDD) and pMOSFET with p-type LDD produces a well-developed cobalt silicide with its lateral growth underneath the sidewall spacer. In case of pMOSFET with n-type LDD, however, a void is formed at the sidewall spacer edge with no lateral growth of cobalt silicide. The void formation seems to be due to a retarded silicidation process at the LDD region during the first Rapid Thermal Annealing (RTA) for the reaction of Co with Si, resulting in cobalt mono silicide at the LDD region. The subsequent second RTA converts the cobalt monosilicide into cobalt disilicide with the consumption of Si atoms from the Si substrate, producing the void at the sidewall spacer edge in the Si region. The void formed at the sidewall spacer edge serves as a resistance in the current-voltage characteristics of the pMOSFET device.

• Journal of the Korean Magnetics Society
• /
• v.17 no.4
• /
• pp.172-177
• /
• 2007

In order to detect of the magnetic property in the cell unit, we studied the GMR-SV (giant magnetoresistance-spin valves) biosensor, which was depended on the micro patterned features according to two easy directions of longitudinal and transversal axes. Here, the multi layer structure was glass/NiO/NiFe/CoFe/Cu/CoFe/NiFe. The uniaxial anisotropy direction was applied to the patterned biosensor during the deposition and vacuum post-annealing at $200^{\circ}C$ under the magnitude of 300 Oe, respectively. Considering the magnetic shape anisotropy effect, the size of micro patterned biosensor was a $2{\times}5{\mu}m^2$ after the photo lithography process. By our experimental results, we confirmed that the best condition of GMR-SV biosensor should be the same direction of the axis sensing current and the easy axis of pinned NiO/NiFe/CoFe triple layer oriented to the width direction of device, and the direction of the easy axis of free CoFe/NiFe bilayer was according to the longitudinal direction of device.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.11a
• /
• pp.112-112
• /
• 2009

In this study, the effect of a long post-deposition thermal annealing(600 and 1000 $^{\circ}C$) on the surface acoustic wave (SAW) properties of polycrystalline (poly) aluminum-nitride (AlN) thin films grown on a 3C-SiC buffer layer was investigates. The poly-AlN thin films with a (0002) preferred orientation were deposited on the substrates by using a pulsed reactive magnetron sputtering system. Experimental results show that the texture degree of AlN thin film was reduced along the increase in annealing temperature, which caused the decrease in the electromechanical coupling coefficient ($k^2$). The SAW velocity also was decreased slightly by the increase in root mean square (RMS) roughness over annealing temperature. However, the residual stress in films almost was not affect by thermal annealing process due to small lattice mismatch different and similar coefficient temperature expansion (CTE) between AlN and 3C-SiC. After the AlN film annealed at 1000 $^{\circ}C$, the insertion loss of an $IDT/AlN/3C-SiC/SiO_2/Si$ structure (-16.44 dB) was reduced by 8.79 dB in comparison with that of the as-deposited film (-25.23 dB). The improvement in the insertion loss of the film was fined according to the decrease in the grain size. The characteristics of AlN thin films were also evaluated using Fourier transform-infrared spectroscopy (FT-IR) spectra and X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM) images.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.06a
• /
• pp.86-87
• /
• 2009

High quality $CuInSe_2$ (CIS) were grown on GaAs substrate by using the hot wall epitaxy method. The behavior of point defects in the CIS layer investigated by using photoluminescence (PL) at 10 K. Point defects originating from $V_{Cu}$, $V_{Se}$, $Cu_{int}$, and $Se_{int}$ were classified as donor or acceptor types. These PL results also led us to confirm that the p-type CIS layer had obviously converted into n-type after the Cu atmosphere treatment. Finally, we found that the In in the CIS layer did not form the native defects, because In existed in the form of stable bonds in the CIS layer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.05a
• /
• pp.133-135
• /
• 2006

SBN60 and SBN60/30 thin films were deposited by ion beam sputtering technique. Using the ceramic target of the same composition and Pt(100)/$TiO_2$/$SiO_2$/Si or Pt(111)/Ti/$SiO_2$/Si substrate, crystallization and orientation behavior as well as electric properties of the films were examined, Thickness was controlled to $3000{\AA}$ and the films were heat-treated at $650^{\circ}C{\sim}800^{\circ}C$. The orientation and crystallization behavior were observed which showed the dependence on processing condition($O_2$/Ar ratio, substrate temp, annealing temp...).

• Proceedings of the KIEE Conference
• /
• 2004.11a
• /
• pp.54-57
• /
• 2004

ZnO thin films on (001) sapphire substrates have been deposited by pulsed laser deposition(PLD) technique using an Nd:YAG laser with a wavelength of 266 m. During deposition, the experiment of the deposition of ZnO thin films has been performed for substrate temperatures in the range of $400^{\circ}C$ and flow rate of 350 sccm, films have been annealed at various substrate temperatures after deposition. After post-annealing treatment in the oxygen ambient, the structural properties of ZnO thin films were characterized by diffraction (XRD), SEM and the optical of the ZnO were characterized by photoluminescence (PL).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.04a
• /
• pp.39-40
• /
• 2008

We have examined post-annealing and passivation for the transparent bottom gate IGZO TFT having an inverse co-planar structure. The oxygen-vacuum two step annealing enhanced the field effect mobility up to 18 $cm^2$/Vsandthesub-threshold swing down to 0.2V/dec. However, the hysterysis and the bias stability problems could not be solved just by post-annealing. Thus, we have passivated the bottom gate IGZO TFTs with organic and inorganic materials. $Ga_2O_3$, $Al_2O_3$, $SiO_2$ and some polymer materials were effective materials for passivations. The hysterysis and the stability of the TFTs were remarkably improved by the passivations. We have manufactured the AMOLED panel with the transparent bottom gate IGZO TFT array successfully.

• Journal of the Korean Electrochemical Society
• /
• v.20 no.3
• /
• pp.55-59
• /
• 2017

In this study, thermoelectric characteristics of perovskite $La_{0.5}Ca_{0.5}MnO_3$ (LCMO) nanomaterials were investigated by theoretical simulation and experimental analysis. Thermoelectric power factors calculated by DFT simulation were gradually enhanced as increase in annealing temperature. Maximum power factor was obtained with high magnitude of $S^2{\sigma}=566{\mu}W/m{\cdot}K^2$ at 1100 K through a dominant improvement of Seebeck coefficient compared with electrical conductivity. Experimentally, the LCMO nanomaterials were hydrothermally synthesized and then treated by post thermal annealing with temperature variation. X-ray diffraction and SEM analysis illustrated that LCMO exhibited orthorhombic perovskite structures with small grain size of 16~19 nm over 873 K. The results directly confirmed that improvement of crystallinity and decrease of mean grain size given by post thermal annealing lead to enhancements of electrical conductivity and Seebeck coefficient, respectively.